1. Field of the Invention
The present invention relates to an electrical assembly having heat dissipation and electromagnetic interference reduction features.
2. Description of Related Art
Electrical devices, and central processing units in particular, draw high power and produce more heat than can be convected away from the dies of the device. If the die temperature exceeds acceptable levels, the device will either cease functioning, not operate at acceptable levels, and/or function in an unreliable manner. In addition, many electrical devices emit electromagnetic interference (EMI) that can adversely affect nearby electronics or electronic communication. The Federal Communication Commission of the U.S. government and industry agencies, such as Telcordia and United Laboratories, have established and verified EMI limits for such electrical devices.
To address this problem, heat dissipation devices are used to convect heat away from electrical devices. Many heat dissipation devices also incorporate EMI reduction features to ensure that government EMI limitations are complied with.
Heat dissipation devices of the prior art have several deficiencies. For example, prior art heat dissipation devices that use a matrix of fins incorporate fins that have inefficient dimensions and that are inefficiently spaced for heat conduction and heat convection purposes. Moreover, many heat dissipation devices incorporate an inefficient cross sectional fin shape, such as an undesirable rectangular shape, that only permits satisfactory heat dissipation when positioned in a first orthogonal orientation. Thus, these heat dissipation devices cannot adequately dissipate heat when positioned in a second orthogonal orientation. This prevents such heat dissipation devices from being used in systems that require the heat dissipation devices to be positioned in a second orthogonal orientation. Moreover, heat dissipation devices of the prior art incorporate heat interface material to allow for thermal communication between the heat dissipation device and the electrical device. The thermal interface material used, however, is expensive.
Heat dissipation devices of the prior art that incorporate EMI reduction features incorporate a compliant member between the EMI reduction feature and the object to which the EMI reduction feature is grounded, such as a circuit board. The compliant member provides better contact between the EMI reduction feature and the circuit board, and thus provides adequate grounding, which is required for acceptable EMI reduction. The complaint member, however, adds extra costs.
Therefore, it would be desirable to provide an electrical assembly that includes heat dissipation and EMI reduction features that is not susceptible to one or more of the shortcomings of prior art devices.